Colortune not sparking on cylinder 2&3

Like the title says, I can't see the flame when these two cylinders are firing. I know it's there, the exhaust baffles get hot, but I just can't see the flame...

Any ideas?

 

Are you doing it in the dark? I had a real hard time seeing the blue flame in broad daylight. I put the little black tube thing around the plug, and that helped some but I still wish I had waited until the evening.

 

If your 2 & 3 Hole are hitting OK ... try raising the rpm's up a little bit to see if you get some color when the Mains kick-in.

If you do you ... you have to check:
Colortune Ext Lead shorting-out
Test Leads with Spark Plug for Spark

Pilot Passages on 2 & 3 not delivering fuel
Or
2 & 3 still too rich and not firing.

Things like the possibility that the Flat Washer and O-ring "Flip-flopped during the install.

"Taste-test" Pilot Passages
(Crude but effective)

Take-out the Screw, spring, washer & O-ring
Put a Hose over the top of the Screw-hole.
Draw on the hose like you are stealing gas.
Taste Gas = Y / N
Yes = Pilot Passages Open / Pilot Jet supplying Fuel
No = Clogged Passage or Jet.

 

I did another round yesterday, and found that there was spark in 2&3 after all. Videos included below. Tell me what you think. The tests were carried out without the YICS tool. Should it be in?

2 is too rich, but this may be caused by a leak between baffle and collector box. Also, the spark comes on some time after 1/3/4, maybe 4-5 seconds. I have to rev it up for it to start sparking.

http://www.youtube.com/watch?v=TqfGfWeJJ0w

3 is too lean, and I can't really see any color, except for a seldom time when it hits light blue.

http://www.youtube.com/watch?v=EQwtxtjUYdw

4 is ok, i guess. Could perhaps be a little richer...

http://www.youtube.com/watch?v=Fo4vTU64

 

Yep. Number-2 is looking lean.
If you can't correct it by smothering the Air Leak and the Spark Plug situation shows that the Hole is CRITICALLY Lean ... Up the Pilot Fuel Jet and see if you can "Play-with-it"

3 has "Flashes of Blue"
On some strokes nothing.
That might be too Rich
(Is the Hole "Misfiring" when theres No Blue?) <----- ####

4. That's what you shoot for. That BLUE ... (or) ... "Just beyond it".
That BLUE is a Guarantee of Great Idle.
But, you have to add a TINY BIT MORE Richness to aid in the sustaining of combustion during ...

The duration of about 3 or 4 rapid "Eye Blinks" of FRESH AIR that precedes the FUEL SUPPLY from the MAIN JETS.

This duration is called: OFF-Idle

At once the Throttles are Opened "Off-Idle" the degree of Supplemental Richness from the Pilot Mixture Screw.

Too much ---> and the Engine Boggs-out for a moment.

Too little ---> and the Engine waits ... "Hesitates" ... until the Main Fuel Supply Mixture takes effect.

Monitor the LEAN Hole.
Keep an eye on the Spark Plugs Ceramic Tower surrounding the Center Electrode.
IF that Ceramic stays CLEAN ... L@@K at it with a Magnifying Glass.
If there becomes any deterioration --- It's CRITICALLY Lean
This includes tiny Stress Fractures that will show-up if the Mixture is too lean.

 

I'll keep an eye on your points. Man I wish there were some skilled xj'ers in Scandinavia....

 

Before you throw-up your hands in frustration; here's something I think you should try.

Take the time to remove the Carbs and SEAL the Intake Manifold to the Head.
Rather than try to tighten what might be seized Manifold Securing Cap Screws and have one or more break, ... Use an RTV Sealant and "TUCK" a SMEAR of Sealant in the Joints where the Manifolds and Heads mate.

Seal them against any AIR Leaking in.

Like a Glaser would Putty the space between the Glass and the Window Frame, ... SEAL the Manifolds to prevent AIR from entering where the Edge of the Manifold meets the Cylinder Head.

There's NO Guarantee this will cure your Not Getting Blue problem.

But, ... it's worth a shot!

 

The thing is, I did that already. The boots into and out of the carbs are all sealed with black RTV.
I can see the intake boots pulsing from the vacuum created by the engine.

Colortune shows no blue on #3, but the spark plug comes out wet (sometimes anyway).
This weekend, I'm going to try with a fresh battery, and possibly also check the coils' voltage...

 

I volunteer for the job (my wife would kill me but I'd love to see Europe!

 

The fact that you find the Plug WET is a good Clue to what might ail you.

For the Carb with the Wet Plug.
You inspect:
The Air Jets for correct placement.
The Throttle Plate for closing
The Pilot Jet for correct size
The Diaphragm Piston for Sticking

++> The Petcock Vacuum Hose for Fuel Leaking from a Perforated Vacuum Membrane.

Out of Round Orifice on the Center Emulsion Tube.

 

The Air Jets are all mounted the same on all carbs.. but I could go over again, I guess...
Pilot Jets all the same on all bodies...
Clunk test shows they all fall... Also I did lift up the pistons when they were all mounted, and they "fall" down at the same rate.
The petcock is overhauled with new internals from Len...

I guess I could check the throttle plate...

 

The Pilot Mixtures are Set to allow the Bike to IDLE.
The Colortune Plug is designed to allow you to FIND the ideal IDLE Mixture.
Bunsen Burner Blue.

The Pilot Mixture is regulated by the Pilot Mixture Screw.
The Technical Term for Pilot Mixture Screw is: Pilot AIR Jet.
The AIR and FUEL for setting IDLE should be supplied by the Pilot AIR Screw ONLY.

If the Throttle Plate is OPEN ... The Pilot Mixture is spoiled with either:
Too much AIR. If the Throttle is very slightly opened.
Too much FUEL. If the Throttle is opened enough to siphon Main Jet Fuel.

To prevent the Pilot Mixture from being spoiled you Bench Sync the Carbs using a FEELER Gauge of the THINNEST Material.

A Narrow Strip of 3X5 Card will slip beneath the Throttle Plates and leave the Throttle Plates Mechanically Synchronized with them being able to be closed for Tuning.

With the Throttles CLOSED the IDLE Mixture will be able to be set by adjusting the Pilot Mixture Screw to deliver the most accurate Air~Fuel Mixture for setting IDLE Speed and SUPPLEMENTAL RICHNESS.

 

Thanks Rick. Just did a compression check today... it's not looking good. I bare got it to 50 psi. Never done a c. check before, so I'll have to repeat it a few times and check the valve clearances...

Thanks for the tips...

 

That's not good.
Those numbers make me want to check if you conducted the Test correctly?

Battery FULLY Charged?
Throttles locked WIDE OPEN?
ALL Plugs Removed?
Black Box Unplugged?

Washer or O-ring on the Threaded Fitting?

If the 50 psi reading don't change ...
Add a tablespoon of Oil to the Cylinder and Re-Test.

Values Increase: Rings
Values No change: Valves.

 

Thanks Rick. Just did a compression check today... it's not looking good. I bare got it to 50 psi. Never done a c. check before, so I'll have to repeat it a few times and check the valve clearances...

Thanks for the tips...

 

50 psi makes me think you erred doing the test.

Battery FULLY Charged? ✔
Throttles FULLY Open? ✔
ALL 4 Plugs Pulled-out? ✔
Ignitor Unplugged? ✔
Reading "PSI"? ✔
Gauge Not Broken? ✔
Several Revolutions of
each Hole measured? ✔

 

Like I said, this is the first time I do a compression test, and I wouldn't rule out human error. In fact, eliminating me having done something wrong is at the top of my list...

 

So, I've finally done it right this time. I let the engine do the cranking work + sealed the gauge with teflon tape on all ends.

All cylinders are within 10% of deviation from each other.
#1: 136
#2: 139
#3: 137
#4: 141

Gotta get more gas and attempt some more tuning while waiting for the valve tool.